TY JOUR TI THE PINE UNDERGROWTH DENSITY INFLUENCE ON BIATORELLA PINE CANCER PREVALENCE KW Biatorella cancer KW disease prevalence KW pine undergrowth KW infection KW cutting down KW maternal crown layer JO Bulletin of KSAU AU Safronova, I.E. AU Sorokin, N.D. PY 2013 IS PB Krasnoyarsk State Agrarian University